The former House speaker's campaign manager, national campaign chair and his longtime spokesman resign after disagreements over Gingrich's commitment to the presidential race.

The top staff of Newt Gingrich's nascent presidential campaign abandoned their candidate Thursday, in a group resignation that followed a series of disagreements over the former House speaker's commitment to the GOP race.

After days of discord over how the campaign should proceed, Gingrich on Thursday lost his campaign manager, Rob Johnson; his national campaign chair, former Georgia Gov. Sonny Perdue; and his longtime aide and spokesman, Rick Tyler; along with key strategists in Iowa, New Hampshire and South Carolina.

The resignations renewed questions that have dogged Gingrich's candidacy from the outset: Did the famously verbose Gingrich possess the discipline to run a campaign in which every remark would be scrutinized? In order to campaign, was he willing to neglect his personal empire of companies that promote his name, his books and, more recently, movies he produced with his wife?

His effort has been troubled from the outset, when he came under fire for criticizing the House GOP's proposal to replace Medicare with a voucher plan and for news that he had a credit line of as much as $500,000 at Tiffany & Co., the posh jewelry store. In recent weeks, as competitors scoured the early voting states, Gingrich took off for a two-week cruise in Greece.

Although some observers said Thursday's news essentially ended his candidacy, Gingrich posted an announcement on Facebook pledging to continue his presidential bid.

"I am committed to running the substantive, solutions-oriented campaign I set out to run earlier this spring," Gingrich wrote. "The campaign begins anew Sunday in Los Angeles." Gingrich will be in California for a Jewish Republican gala where he will speak on the Middle East and U.S. foreign policy.

Arizona Sen. John McCain faced a similar wave of resignations from his 2008 campaign and went on to capture the nomination. But the situation facing Gingrich is more dire.

Craig Robinson, a former political director of the Iowa GOP, said the Gingrich campaign "is effectively over. Here and nationally."

The news buoyed former Minnesota Gov. Tim Pawlenty, who announced that Perdue, Gingrich's former national chair, would join his campaign.

And it fueled speculation that Texas Gov. Rick Perry might enter the race, in part because two of Perry's former top advisors were among those who quit the Gingrich campaign. Among them was Johnson, Gingrich's campaign manager, and his New Hampshire strategist, Dave Carney.

A Perry advisor, who was not sanctioned to speak publicly, said "speculation will become more intense" about a Perry run now that Carney and Johnson are no longer tied to another candidate. But Thursday's moves reflected change in Gingrich's campaign, not a sign that the Texas governor is preparing to run, he said.

Interviews with two departing Gingrich staffers revealed a deep rift between the candidate and his staff over campaign basics. Gingrich, they said, would not agree to concentrate his time on grass-roots campaigning in early states. And he refused to commit to a fundraising schedule necessary to amass a reasonable campaign treasury.

"My idea of what it would take to win was different from that of the Speaker and, given those differences, I felt that I had to leave," said Tyler, who added that he had only a brief conversation and email message exchange Thursday with his longtime boss.

Craig Schoenfeld, the former House speaker's top Iowa advisor, told close associates he was leaving because of Gingrich's lack of commitment to pursuing a "path to victory," including a rigorous Iowa grass-roots schedule.

Gingrich's staff troubles began during his recent cruise when a prominent Iowa campaign organizer, Will Rogers, resigned and said he was concerned about Gingrich's commitment there.

The most recent departures struck closer to Gingrich's inner circle; Tyler had worked with Gingrich in his political and private enterprises for years. He said he would not remain associated with Gingrich going forward, though he wished him well. "I will find a new path," he said, adding. "I don't know what it is yet."

The news comes only days before Gingrich is to participate in a debate with six other Republican presidential hopefuls in New Hampshire, the first significant forum of the primary season.

Ken Khachigian, a veteran GOP strategist, said that Gingrich's mistakes were serious but not yet fatal. "Newt's a smart guy, and if he will put his very strong ego aside, he'll assess what's going on and redirect his campaign," Khachigian said. "If you really want to be president, you're going to have to do the work."

In Washington, a newly designated spokesman for the Gingrich campaign, Joe DeSantis, said the former speaker is absolutely committed to running.

"He's looking forward to his speech in L.A. Sunday and the debate Monday," DeSantis said in an email.